package com.itheima.test.producer;

import org.apache.kafka.clients.consumer.*;
import org.apache.kafka.common.TopicPartition;

import java.time.Duration;
import java.util.Collections;
import java.util.Map;
import java.util.Properties;

/**
 * 消费者
 */
public class ConsumerQuickStart100 {

    public static void main(String[] args) {
        //1.添加kafka的配置信息
        Properties properties = new Properties();
        //kafka的连接地址
        properties.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.200.130:9092");
        //消费者组   同一个组下消费者订阅同一个主题，消息只能被其中一个消费者取走     如果是不同组下消费者订阅同一个主题他们都可以消费到同一条消息
        properties.put(ConsumerConfig.GROUP_ID_CONFIG, "group3");
        //消息的反序列化器
        properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
        properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
        properties.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, false);//关闭消费者自动提交偏移量

        //2.消费者对象
        KafkaConsumer<String, String> consumer = new KafkaConsumer<String, String>(properties);

        //3.订阅主题
//        consumer.subscribe(Collections.singletonList("itheima-topic114-1"));

        //只消费itheima-topic114-1  的0号分区
        TopicPartition topicPartition = new TopicPartition("itheima-topic114-1", 0);
        consumer.assign(Collections.singletonList(topicPartition));

        //当前线程一直处于监听状态
        while (true) {
            //4.获取消息
            ConsumerRecords<String, String> consumerRecords = consumer.poll(Duration.ofMillis(1000));
            for (ConsumerRecord<String, String> consumerRecord : consumerRecords) {
                System.out.println(consumerRecord.key());
                System.out.println(consumerRecord.value());
            }

            //同步提交偏移量（消费者消费到哪了）
            try {
                consumer.commitSync();//同步提交当前最新的偏移量
            }catch (CommitFailedException e){
                System.out.println("记录提交失败的异常："+e);
            }


            //异步提交偏移量
            consumer.commitAsync(new OffsetCommitCallback() {
                @Override
                public void onComplete(Map<TopicPartition, OffsetAndMetadata> map, Exception e) {
                    if(e!=null){
                        System.out.println("记录错误的提交偏移量："+ map+",异常信息"+e);
                    }
                }
            });
        }

    }

}